<style>
  * {
    padding: 0px;
    margin: 0px;
  }
  div {
    width: 300px;
    height: 300px;
    background-color: skyblue;
  }
  div p {
    background-color: seashell;
    padding: 30px;
  }
</style>
<!-- 如果没有设置 padding，不会撑开盒子 -->
<body>
  <div>
    <p>
      Lorem, ipsum dolor sit amet consectetur adipisicing elit. Vel alias
      voluptatum velit?Lorem, ipsum dolor sit amet consectetur adipisicing elit.
      Vel alias voluptatum velit?
    </p>
  </div>
</body>
